Respiratory masks



y 7, 1957 J. A. CHURCHILL ET AL 2,791,216

RESPIRATORY MASKS Filed Feb. 15, 1955 3 Sheets-Sheet 1 l W F \NVENTORS 'Faeoamc R. STANLEY JOHN A Cuuacr-uu.

w ATTORNEYS J. A. CHURCHILL ETAL 2,791,216

May 7, 1957 RESPIRATORY MASKS 3 Sheets-Sheet 2 Filed Feb. 15, 1955 INVENTORS FREDERIC. R STANLEY JOHN A. Cnunzcp-uu.

aw M ATTokNEYs y 1957 J. A. CHURCHILL ET AL 2,791,216

RESPIRATORY MASKS 3 Sheets-Sheet 5 Filed Feb. 15, 1955 NV ENTORS United States Patent RESPIRATORY MASKS John Adrian Churchill, Luton, and Frederic Reginald Stanley, London, England, assignors to Martindaie Electric Company Limited, London, England, a British company Application February 15, 1955, Serial No. 488,228

Claims priority, application Great Britain February 22, 1954 7 Claims. (Cl. 128-146 This invention relates to respiratory masks of the kind comprising a part (hereinafter referred to as a cup) arranged to fit over the nose and mouth of the wearer so that the edge or mouth of the cup makes a substantially air-tight seal with the wearers face. Such masks may be used as dust masks for instance, in which case they may be combined with a filter casing, containing a filter pad, connected to the base of the cup, in which base is formed an inspiratory opening communicating with the interior of the filter casing and controlled by an inspiratory valve permitting flow" of air through the filter pad into the cup but not in the opposite direction, and one or more expiratory openings in the wall of the cup controlled bypa valve or valves arranged to 'permit flow of used air out of the cup into the atmosphere but not in the opposite direction. Themasks may however be used for other respiratory purposes, such as the administration of anaesthetics, in which case the cup 'portiono'f the mask will usually be connected directly to the supply of anaesthetic. In any case it is usual in use to provide a detachable fabric covering which fits around the mouth of the cup in a readily detachable and replaceable manner to absorb moisture which otherwise might accumulate at this point.

In one form of such a respiratory mask as at present made the cup is formed of hard moulded material as a unit with the base of a filter casing, the latter being in the form of a cylindrical casing of relatively large diameter and small depth in which the filter pad is normally retained by a screw-on perforated cap or lid, the expiratory opening or openings being formed in the lower wall of the cup while, secured around the mouth of the cup, is a thick pad of sponge rubber or the like of such dimensions and flexibility as to enable it to conform to a variety of facial contours.

It is an object of the present invention to provide a respiratory mask of the kind referred to which can be more readily manufactured than the known type of mask, will be comparatively inexpensive, will at the same time provide for wide variations in the facial contours of different wearers, and will have other advantages.

The invention may be performed .in various different ways but three specific embodiments will now be described by way of example with reference to the accompanying drawings in which:

Figures 1 and 2 are front and rear perspective views of a mask according to the invention, combined integrally with a filter container,

Figure 3 is a sectional side view of the mask shown in Figures 1 and 2,

Figure 4 is a sectional side view of a modified mask combined with a detachable filter container, and

Figure 5 is a side elevation partly in section of a mask according to the invention combined with a separate filter container to which it is connected by a length of flexible tubing.

In the first example of the invention illustrated in cave recess 5 are two circular expiratory openings 9,

2,794,216 Patented May 7, 1957 Figures 1, 2, and 3 the cup of the mask has an approximately triangular base 1 and is of approximately triangular form in cross sections parallel to that base, the triangle being isosceles with the two equal sides longer than the third or lower side. The two equal side walls 2 and 3 of the triangular cup are arranged to lie one on each side of the wearers nose while the lower wall 4 engages and extends around the wearers chin just below the mouth, for which purpose it is formed with a cut-away downturned recess 5.

The cup itself is formed of a flexible synthetic plastic material such as polythene, and is preferably moulded. Moulded into a bead 6 adjacent to the edge 7 of the mouth of the cup but slightly spaced therefrom is a ductile metal wire 8 of tortuous form which not only assists in the provision of the bead extending around this edge but also enables the edge to be bent to conform to the contours of the 'Wearers face and then to retain this edge in approximately the form into which it is bent. The wire 8 is in the form of a coiled helix, which assists in locating the wire in the correct position when the mask cup is moulded, and also reduces the degree to which any part of the wire must be bent, since the 'total length of wire is increased. The extreme edge or lip 7 of the mask cup is turned outwardly to provide a thin bell month, which thus lies flush with the face of the wearer,

and by its resilience affords an etiicient air-tight seal. If desired a detachable fabric covering may be fitted over the lip 7, to absorb moisture.

'Formed in the lower Wall 4 on each side of the coneach having associated therewith anon-return valve of the known type including a flexible "disclO of rubber or similar material. f.

Formed in the triangular base 1 of the cup at about the centre of its area is an inspiratory opening 11 controlled by a similar flexible disc-type one-way valve 11a. Formed integral with the base of the cup is a triangular box-like filter container 12 of approximately equilateral triangular form with the upper apex of the triangle lying just above the inspiratory opening 11 of the mask cup, which thus opens into the interior of the filter container. This container 12 contains a triangular filter pad (not illustrated) and has a detachable perforated front wall or lid 13 for the admission of air and for the removal and replacement of the filter pad. Formed or arranged on the inner wall 14 of the container is a series of thin relatively deep ribs 15 extending from points adjacent to the lower wall 16 of the container towards the inspiratory opening 11 so as to form between them and the inner face of the filter pad a series of passages by which air can pass from the different areas of this inner face to the inspiratory opening. The lid 13 of the container is also formed with similar relatively narrow and deep ribs 17, which permit air to be drawn readily into and through the filter pad.

The mask is conveniently held in position on the wearers face by an elastic strap 19, and for this purpose the two side walls 2 and 3 are provided with stud fasteners 18.

The modified construction illustrated in Figure 4 is in all respects identical with that described above, except only that the filter container 12 is detachable from the mask cup. To this end the base wall 1 of the mask cup is formed with a corresponding tubular extension 21 which makes a tight fit within the socket 20. In this case the inspiratory valve disc 11a is conveniently mounted on the end of the tubular extension 21. This construction enables a complete filter container with a fresh filter pad to be substituted for a used filter.

In the construction illustrated in Figure 5 the mask cup is combined with a separate filter unit 22 to which it is connected in a manner known per se by means of. a flexible tube 23. In this case the mask cup itself is preferably identical with the form illustrated in Figure 4, including a socket formation 20 formed on the base wall 1 of the cup. A corresponding tubular member'24 is secured to the end of the tubular connection 23 and is arranged to make an air-tight seal when it is inserted into the socket 20. The inner end of the member 24 is formed with a flexible disc valve 25 corresponding to the inspiraatory valve 11a in the previous constructions, and arranged to permit air to be drawn into the mask through the filter unit 22, but to prevent air passing in the 'reverse direction.

It will be understood that when usedfor administering anaesthetics, oxygen, or other gas,the construction of'the mask may be the same, but it will be connected to a gas supply rather than to the filter unit 22.

What we claim as our invention and desire to secure by Letters Patent is:

1. A respiratory mask of the kind comprising a cup part arranged to fit over the nose and mouth of the wearer, to make a substantially airtight seal with the wearer's face, the cup being formed of a flexible plastic material having a ductile metal element of tortuous form extending around and secured to its edge or mouth so that the edge portion of the cup can be bent to conform to the contours of the wearers face, and will then be retailed by the tortuous ductile element in substantially the form into which it has been bent.

2. A respiratory mask as claimed in claim 1, in which the ductile element is in the form of a helical coiled length of wire.

3. A respiratory mask as claimed in claim 2, in which the ductile metal element is moulded into a beading or thickened portion of the cup and is spaced somewhat from the extreme lip of the mouth of the cup this lip being turned outward to form a flexible bellmouth.

4. A respiratory mask as claimed in claim 1, in which the base of the cup is connected to a filter container which is generally in the form of an isosceles triangle, in vertical sections, with apex of the triangle uppermost.

5. A respiratory mask as claimed in claim 4 in which the cup portion of the maskis also of generally isosceles triangular form in vertical section, with the apex of the triangle uppermost, and in which the filter container is arranged generally below the level of the cup.

6. A respiratory mask as claimed in claim 4 in which the cup is formed to provide an inspiratory opening communicating with the filter container, and the wall of the filter container'adjacent the inspiratory opening of the cup is provided with a series of narrow ribs, which space the filter pad away from this wall, and are formed and arranged to provide between them a series of passages extending towards the inspiratory opening from parts of the filter pad remote therefrom.

7. A. respiratory mask as claimed in claim 4, in which the filter container is provided with a movable lid, to permit the filter pad to be replaced, the lid being perforated and formed with comparatively narrow and deep ribs which engage the adjacent face of the filter pad to hold it in place so as to provide a comparatively rigid perforated structure to hold the pad in place while obstructing as little as possible the passage of air through the outer face of the filter pad.

References Cited in the file of this patent UNITED STATES PATENTS 366,759 Byrnes July 19, 1887 2,591,953 MacLean Apr. 8, 1952 2,668,532 Evans Feb. 9, 1954 FOREIGN PATENTS 705,842 Germany May 12, 1941 

